Asplenium septentrionale is the autotetraploid that originated by chromosome doubling in its diploid ancestor A. caucasicum. In the absence of a chromosome count, it can best be distinguished by its larger mean exospore length (more than 37 µm) and its broader lamina.

Asplenium septentrionale often hybridizes with other Asplenium species in Europe wherever they co-occur; one of these, A. ×heufleri Reichardt (A. septentrionale × A. quadrivalens), was recently found in Xinjiang.